With downsizing, weight reduction, and enhancement in performance of electronics, semiconductor devices have increased calorific values and raised heat density. In addition, in flip-chip type semiconductors, with decrease in dielectric constant of interlayer insulating films, destruction due to stress has become a problem. Further, semiconductors having a wide band gap, such as silicon carbide and gallium nitride, as a power semiconductor are under consideration. A power semiconductor using a semiconductor having a wide band gap is capable of being operated at a higher temperature compared with a conventional silicon semiconductor.
As an electrically conductive bonding material suitable for a semiconductor device operated at a high temperature, Patent Literature 1, for example, describes an electrically conductive bonding material including as an aggregate, a metal fine particle made of a first metal and capable of being sintered at a temperature lower than a melting point of the first metal; and a metal coated resin particle having a resin particle with a particle diameter larger than the metal fine particle coated with a second metal that is capable of being sintered with the first metal.
As a flip chip type semiconductor device and a manufacturing method thereof, Patent Literature 2, for example, describes a method of manufacturing a flip chip type semiconductor device including performing the steps, in this order, of: while electrically connecting an electrode unit provided on a substrate made of an organic material and a bump electrode of a semiconductor device, arranging the semiconductor device on the substrate; plasma processing a surface of the substrate; and, after filling predetermined underfill in a gap between the substrate and the semiconductor device, sealing the gap by thermosetting the predetermined underfill.
In addition, as a method of manufacturing a bump of a semiconductor device, Patent Literature 3, for example, discloses a method of manufacturing a bump for connecting an electrical circuit characterized by applying a predetermined bonding agent for a metal member in dots on a pad unit for connecting an electrical circuit on a semiconductor device or on an electrode unit for connecting an electrical circuit on a substrate and heating at not less than 70° C. and not more than 400° C., thereby sintering the metal particles with each other to form a bump made of metal on the semiconductor device or the substrate. In addition, Patent Literature 3 describes that the predetermined bonding agent for a metal made member is a pasty substance, including (A) heat sintering metal particles having an average particle diameter (median diameter D 50) of more than 0.1 μm and not more than 50 μm and having a melting point of higher than 400° C. and (B) a liquid flux, wherein the metal particles (A) are sintered with each other by being heated at not less than 70° C. and not more than 400° C. to become a porous sinter having a melting point equivalent to the metal particles (A) and also having adhesiveness to the metal member that is in contact during the sintering.
In addition, Patent Literature 4 describes, as a bump of a semiconductor device, a carbon nanotube bump structure that is composed of a carbon nanotube (CNT) and a metal coating portion selectively coating one end side of the carbon nanotube. Further, Patent Literature 4 describes a proposed method of applying a carbon nanotube (CNT) to a bump electrode as a method of suppressing electrode disconnection due to the high current density carried by the semiconductor chip and destruction due to the stress.
Patent Literature 5 describes silver fine particles having an average particle diameter of primary particles from 40 to 350 nm, having a crystallite diameter from 20 to 70 nm, and having 1 to 5 of a ratio of an average particle diameter to a crystallite diameter. The invention described in Patent Literature 5 is described to have an object of providing silver fine particles for a raw material of an electrically conductive paste exhibiting sufficient electrical conductivity at a firing temperature of 200° C. or less and an electrically conductive paste containing the silver fine particles. Specifically, it is described that an electrically conductive paste containing the silver fine particles described in Patent Literature 5 may be used to form a circuit pattern that is more miniaturized.